1. Field of the Invention
The invention relates to a parking meter for renting a parking space for a period of time. More generally, the invention relates to a time meter for dispensing time in return for money.
In the art of money operated timing devices, coin operated parking meters are well known. Typically, a parking meter is mounted on a stand situated on a boulevard adjacent a curb on a street. The street is usually marked with painted lines to indicate a parking space which is controlled by the parking meter. A driver wishing to park a car in the space controlled by the meter simply parks in the space and then deposits coins in the meter to purchase a period of parking time.
A parking meter such as that described in U.S. Pat. No. 4,792,032 to Shapiro has a mechanism including a plurality of contacts which are used to sense the denomination of each coin inserted into the meter. The contacts provide electric signals to an electronic circuit which meters parking time and maintains a visual display of remaining parking time. The circuit is contemplated as being a retrofittable upgrade to existing meters. The circuit has the capability that the parking rate (i.e. time per unit of money) and the maximum permitted parking time can be programmed by switches to any of a plurality of values. The contacts of the Shapiro device could however, be susceptible to corrosion and fouling due to dirt which may accumulate thereon over time. Corroded or dirty contacts can lead to unreliable operation of the meter leading to loss of revenue to the owner of the meter. When the circuit is a retrofittable upgrade, an installer is required to solder connecting wires to a printed wiring board having copper contact pads and is required to solder contacts onto a coin path of the device. These steps do not render the process of installing the upgrade an easy task as considerable time is required to perform the steps. In addition, the switches used to set the parking rates and maximum time values of the meter must be set while the meter is open and therefore may only practically be set when the meter is in a repair shop or when the meter is open for removal of money. This means that setting the switches is time consuming and provides an opportunity for an error to occur in the setting. Thus, the meter cannot practically meter time at several different rates during different intervals of the day.
U.S. Pat. No. 4,228,519 to Pfeifer discloses a system which employs a plurality of parking meters, each of which is connected to a central control unit. The central control unit and each of the parking meters contains its own microprocessor. The central control unit contains information relating to various tariffs (rates) and times during which the various rates are in effect and continuously transmits this information to the parking meters. The individual parking meters thus meter parking time at any of a plurality of predefined rates. The Pfeifer device, however, requires the use of the central control unit which would be difficult and expensive to install in a parking area such as found in a large airport or a major city as wiring costs and labor costs would be enormous.
U.S. Pat. No. 4,379,334 to Feagins Jr. et al. discloses an electronic parking meter which computes a length of time purchased from the amount of money inserted into the meter in accordance with any of a plurality of rates which may be in effect. The meter dispenses a parking ticket which the vehicle driver places in a window of the vehicle to indicate that parking time has been purchased. The meter keeps a lot status log containing supervisory information such as number of transactions, total receipts, etc. useful in determining appropriate intervals for cash box removal. This meter would be impractical for use on city streets due to the expense of having ticket dispensing equipment in each meter.
In view of the above patents, other patents in the field of parking meters, and market requirements, it would appear there is a need for a self contained parking meter which eliminates the mechanical timing mechanism of prior art devices and replaces that mechanism with an economical, yet versatile electronic timing circuit. In eliminating the mechanical timing mechanism, it is desirable to refrain from the use of electrical contacts in a coin sensing portion of the circuit to avoid the problems associated therewith. In such a device, it is desirable to include provisions for permitting a variety of operating parameters such as parking rates, etc. to be stored and changed easily without excessive effort. Furthermore, it is desirable to provide a device which permits automatic parking rate adjustment according to the time of day and which provides status information to enable meter usage to be evaluated. In addition there is a need for a retrofittable upgrade kit having the above features but which is easy to install in conventional mechanical parking meters.